Contact pin with ceramic insulation

ABSTRACT

In the contact pin with ceramic insulation, one end is provided with a tongue for receiving a pole shoe and the other end is provided with a step which rests against a corresponding step in the flat channel running through the ceramic insulation. The first step of the contact pin is followed by a second step which projects slightly out of the channel and is provided with an upsetting.

The subject of the invention is a contact pin with ceramic insulationwhich is provided at one end with a tongue for receiving a pole shoe andat the other end has a step which rests against a corresponding step inthe flat channel running through the ceramic insulation.

Contact pins of the type mentioned are known. They are used as currentsupply for electric lamps, in particular for halogen lamps. Adisadvantage of the known contact pins is that the connection of thecurrent-carrying conductor to the ceramic insulation is not free oflooseness, and this leads to vibrations of the incandescent coil andconsequently adversely affects its service life. In the case of contactpins spray-coated with plastic, although the metal/insulation connectionis free of looseness, at elevated temperatures to which the contact pinsare exposed, volatile substances are given out as gas and these depositon the reflector of the lamp. At sufficiently high temperatures, theinsulation loses its shape.

It is here that the invention seeks to provide a remedy. The inventionachieves the object by the fact that the first step is followed by asecond step which projects slightly out of the channel and is providedwith an upsetting.

The second step may have an undercut. Instead of the second step on thecontact pin, the ceramic insulation may be provided with recesses whichcut the flat channel laterally and the contact pin may have upsettingsin the region of said recesses.

The advantages achieved by the invention are essentially to be perceivedin the looseness-free, positive connection between metallic contact pinand ceramic insulation.

The invention is explained below in greater detail with reference to thedrawings, which show exemplary embodiments. In these:

FIG. 1 shows a view of the contact pin with ceramic insulation,partially sectioned;

FIG. 2 shows the plan view of FIG. 1;

FIG. 3 shows a view of the contact pin with ceramic insulation in analternative embodiment and

FIG. 4 shows the plan view of FIG. 3.

The contact pin 1, which is composed of electrically conducting materialsuch as steel, copper, tungsten and the like, is provided with a ceramicinsulation 2. The ceramic insulation 2 has a flat channel 3 which isprovided with a step 4. The contact pin 1 is provided with a flap 12 atongue 5 for receiving a pole shoe and with at least one step 6 whichrests against the step 4 of the flat channel 3. In the embodimentaccording to FIGS. 1 and 2, the contact pin has a further step 7 whichvertically projects slightly (1 -3 mm) out of the flat channel 3. Saidstep 7 is provided with an upsetting 8 on the top horizontal surface ofthe step 7, which can extend over the entire perimeter of the step 7 Theupsetting 8 in conjunction with step 6, connects the contact pin 1positively and looseness-freely to the ceramic insulation 2. It may beof advantage to provide the step 7 with an undercut 9. In the embodimentaccording to FIGS. 3 and 4, instead of the second step on the contactpin 1, the ceramic insulation 2 is provided with recesses 10 which cutthe flat channel 3 laterally. In the region of the recesses 10, thecontact pin has upsettings 11. The upsettings 8, 11 on the contact pincan be produced in a manner known per se. Hot upsetting has been foundto be particularly advantageous. For this purpose, the contact pin isbrought electrically to hot forming temperature.

We claim:
 1. A contact pin with ceramic insulation which is provided atone end with a tongue for receiving a pole shoe and at the other end hasa step which rests against a corresponding step in a flat channelrunning through the ceramic insulation, wherein the first step isfollowed by a second step which vertically projects slightly out of thechannel and is provided with an upsetting on the top horizontal surfaceof said second step.
 2. The contact pin as claimed in claim 1, whereinthe second step (7) has an undercut (9) .
 3. A contact pin with ceramicinsulation which is provided at one end with a tongue for receiving apole shoe and at the other end has a step which rests against acorresponding step in a flat channel running through the ceramicinsulation, wherein the ceramic insulation (2) is provided with recesses(10) which cut the flat channel (3) laterally and the contact pin (1)has upsettings (11) in the region of said recesses (10).
 4. A contactpin with ceramic insulation which is provided at one end with a tonguefor receiving a pole shoe and has another end which comprises a flapwhich extends out of the ceramic insulation, a first step which restsagainst a corresponding step in a flat channel running through theceramic insulation, and a second step which lies between said flap andsaid first step and which projects slightly out of the channel in avertical direction, and is provided with an upsetting.
 5. The contactpin as claimed in claim 4, wherein the upsetting extends over the entireperimeter of the second step.
 6. The contact pin as claimed in claim 4,further comprising a vertically extending undercut which lies betweensaid flap and said second step.